Fire detector systems are available to sense various attributes of a fire and to warn individuals when a fire is detected. For example, smoke detectors include sensors adapted to sense smoke associated with a fire and to alarm when a sufficient amount of smoke is detected. Other detectors sense other attributes associated with a fire.
For example, flame detector systems utilizing ultraviolet (“UV”) sensors are known. In a flame detector system, UV radiation emitted from the flames of a fire is detected by the detector's UV sensor. When a sufficient amount of UV radiation is detected, the flame detector system alarms to warn individuals of a flame.
However, there are challenges associated with using flame detector systems with UV sensors to sense flames. For example, UV radiation is emitted from many sources other than the flames of a fire. For instance, sunlight emits UV radiation. It can therefore be difficult to distinguish between UV radiation given off from a flame and other sources of UV radiation, such as sunlight, which do not require alarming. Consequently, the sensitivity of the flame detector systems, and how such systems are configured to process UV radiation, can be important to minimize false alarming while providing adequate protection in case of a fire.
Other challenges associated with this type of flame detector system involve the sensor used to detect the UV radiation. Typically, a UV sensor can be constructed of a sealed UV glass tube with a pair of electrodes and a reactive gas enclosed therein. A constant voltage is typically applied across the UV sensor in order to adequately sense UV radiation. In the presence of UV radiation of a certain wavelength (typically in the range of 100–300 nm), the sensor discharges the voltage to indicate detection of UV radiation. After the UV sensor discharges, the voltage across the sensor must be refreshed to allow the sensor to continue to detect UV radiation. Typically, once a UV sensor discharges, it is refreshed at a periodic interval.
The performance of the UV sensor is known to degrade over time. It can therefore be important to monitor the performance or “health” of the UV sensor to identify when performance of the sensor degrades.
It is therefore desirable to provide flame detector systems that overcome one or more of these challenges and provide additional benefits over prior flame detector systems.